This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Bellows-type air springs or folding-bellows-type air springs are known in the prior art. DE 1 914 391 U discloses a bellows-type air spring having two or three toroidal parts separated by metal intermediate rings, in which the intermediate rings are formed by perforated metal plates that have the cross section of a horizontal eight in order to achieve better centering and better transverse stability of the air spring.
Bellows-type air springs or folding-bellows-type air springs of conventional design have the disadvantage that, when subjected to heavy loads and transverse forces acting on the air spring, adjacent toroidal parts or folds come into contact either with one another and hence into frictional contact or with adjoining connecting sections. Thus, contact can occur between adjacent toroidal parts or folds particularly in the case of folding-bellows-type air springs for street cars or rail vehicles, which must have only a relatively small overall height. The frictional contact which occurs here can lead to severe heating of the bellows sections that are correspondingly in contact, which are then subject to increased frictional wear. In extreme cases, this can lead to parts of the fabric plies arranged as reinforcing elements in the bellows wall being exposed.
DE 475626 C discloses an air spring for a motor vehicle in which the metal rings consist of annular plates of a width such that the annular plates can completely support the individual tubular portions or toroidal parts when subject to a load without the adjacent toroidal parts coming into contact. Although the problems with frictional wear which have been mentioned are somewhat mitigated here by the friction occurring only between rubber and metal, they are far from being prevented to a satisfactory extent.